THE IMPORTANCE OF THE ITERATIVE RECONSTRU CTION ISA IN DIAGNOSING LIVER HEMANGIOMA

Aim: io evaluate whether the iterative reconstruction methodology ISA is superior to the standard technique of filtered back-projection. Met hods: In a retrospective study, we evaluated images of 39 patients wit h solitary or multiple liver tumors who underwent blood pool imaging i n SPECT technique in order to prove or exclude the presence of hemangi oma. Results: Activity accumulations in accordance with the diagnosis of liver hemangioma could be visualized in 34 cases by the iterative, in 31 cases by the filtered back-projection methodology. As compared t o filtered back-projection, the iteratively reconstructed lesions show ed higher tumor-to-background ratios and were more easily distinguishe d from structures in their neighborhood. Furthermore, the iterative me thodology resulted in a more homogenous activity distribution in the l iver, whereas the inhomogenous ''patchy'' structure of the liver paren chyma in filtered back-projection provokes difficulties in the distinc tion from reconstruction artifacts. A clearer visualization of vessels and a better distinction between the right kidney and the liver was p ossible by the iterative algorithm, leading to advantages in the recog nition of centrally or dorsally located lesions in the right hepatic r obe. Conclusion: These data indicate that the use of our iterative alg orithm in performing liver blood pool imaging yields a higher sensitiv ity and a better diagnostic accuracy in diagnosing liver hemangioma.